I have produced the following update using 11 points between 13-18 Jan: USA 129 15.0 3.0 0.0 5.1 v 1 24680U 96072 A 97 18.85811921 .00006385 00000-0 65978-4 0 08 2 24680 97.8745 84.2363 0552461 70.2327 255.0973 14.72378315 04 The ndot/2 of 0.00006385 is within about 2 percent of the mean value over this 5 day period. Taking a 4 day period, 14-18 Jan, the ndot/2 falls by at about 7 percent. Pierre Neirinck has obtained a similar result. Here are the observations, in Elcor format, followed by the residuals: Obs 26 1997 jan 13 1143:26.58 -31.125556 149.11444 390 12.200000 -64.516667 1 Obs 27 1997 jan 13 1144:50.50 -31.125556 149.11444 390 10.270000 -59.883333 1 Obs 28 1997 jan 13 1320:41.30 -31.125556 149.11444 390 23.443333 -52.716667 1 Obs 29 1997 jan 13 1323:36.48 -31.125556 149.11444 390 01.150000 -25.900000 1 Obs 31 1997 jan 14 1212:54.52 -31.125556 149.11444 390 05.616667 -79.933333 1 Obs 32 1997 jan 14 1213:25.43 -31.125556 149.11444 390 05.101667 -71.300000 1 Obs 33 1997 jan 15 1912:00.80 -33.942400 18.51320 10 10.580000 -23.200000 1 Obs 34 1997 jan 15 2049:52.50 -33.942400 18.51320 10 07.748333 -73.866667 1 Obs 35 1997 jan 16 1940:15.60 -33.942400 18.51320 10 10.610000 -27.683333 1 Obs 36 1997 jan 17 2006:29.10 -33.942400 18.51320 10 12.126667 -50.566667 1 Obs 37 1997 jan 18 2035:41.50 -33.942400 18.51320 10 10.681667 -64.533333 1 Residuals ------------------------------ Obs 26 0.0004 Obs 27 0.0002 Obs 28 0.0004 Obs 29 0.0008 Obs 31 0.0005 Obs 32 0.0007 Obs 33 0.0008 Obs 34 0.0004 Obs 35 0.0007 Obs 36 0.0007 Obs 37 0.0001 RMS 0.0003 radians Ted Molczan